where can I see if employees make changes to their payroll account using the workforce app?

You'll receive an email informing you that your employee has made changes to their personal info through your QuickBooks Online Payroll account. These changes will be visible immediately in the Employee profile, @smcl.

Disclaimer: I found this information in an article in the US region and it should work for Canada region in one way or another.

Also, you may find the What happens next section helpful in the following article to see what your employee can manage to edit from their personal info in workforce: Invite employees to QuickBooks Workforce.

Let us know in the comments below if you have any follow-up questions about managing your QuickBooks Workforce.